Poll: Algorithm Type - strong views/preferences?

[aquacat8]

@dmaziuk and @Dr Simon Mitchell thanks for taking the time to answer my question!

 

[uncfnp]

Speaking purely recreationally, if computer 1 with “A” algorithm gives 30 minutes BT and computer 2 with “B” algorithm gives 25 minutes, for 2 otherwise identical dives, How can computer 2 not be considered more conservative?

 

[Jay]

I agree and even started a thread on this problem some time ago. In decompression algorithms, the word "conservative" is associated with staying deeper longer on your ascent. This is opposed to an "aggressive" profile that has you ascending to shallower depths earlier in the ascent. This implies that a "conservative" profile" is SAFER than an "aggressive" profile. Stating this overly simply, research is indicating profiles that leave you deeper longer do not do as well as profiles that get you shallower sooner.

In terms of decompression, the word "conservative" does not necessarily equate to "safer."

Was this in applicable to Rec or Tec (or both) - would you have a link for that?

I guess I should have said - I have no idea how what you are saying applies to me. In other words I'm confused. The Icon uses a RGBM model and I've been told that it's very conservative - some say too conservative.

Is this an issue for me? - in other words less effective and somethig I need to be aware of? I don't spend much time deep on any dive and most of my time is spent above 60'. Average depths range 20-40 something.​

Speaking purely recreationally, if computer 1 with “A” algorithm gives 30 minutes BT and computer 2 with “B” algorithm gives 25 minutes, for 2 otherwise identical dives, How can computer 1 not be considered more conservative?

I'm interested in how a Rec diver should gauge / define conservatism (where Rec = inside Rec limits, rec ascent rates, a typical rec SS etc - i.e. there's no entering a deco obligation). I've given that definition a crack on another thread here too First Dive Computer post #99 , and I see the same question has been asked above ... to me, in the Rec world, it 'seems' an easier answer

I see / think I understand why in the Tec sense of the word it's meaning can be ambiguous from the above posts and also from post #2 here by @KenGordon Contradictions in conservatism (or safety)?

 

[Carlos Danger]

I used a ZHL-12 based product years ago, but seemed like I was getting penalized somewhere and having to start the end of my dives too soon. The ZHL-8 ADT (MB) suites me just about right; always feels more naturally in sync with my profile.

 

[Dan_P]

Similarly, if you eat a mammoth hot fudge sundae and then don't eat anything else for 3 days, it could be argued that mammoth hot fudge sundaes are part of a calorie reduction diet plan.

I'd argue it'd be like elephant hot fudge sundaes are a part of a dietary survival kit - but in either case I'm not advocating or defending the use of the word 'conservatism'; simply trying to deduct what the logic of the choice of word might be is all

 

[Rollin]

This is one of the many: Proceedings of Reverse Dive Profiles Workshop.

Thank you! However, I realise now that in my language, by "dive profile" we mean the depth profile of a single dive. By a normal profile, the diver goes deep first and shallow later, diving a reverse profile, we start shallow (e.g. shore dive) and end up deep. Of course ending the dive with all the required stops.

I was aware of the above, but it is good to see it confirmed.

 

[Kharon]

Seems like a goodly section of this thread is more appropriate to the tec forum. Perhaps it should be split off to avoid confusion by rec divers.

 

[boulderjohn]

Was this in applicable to Rec or Tec (or both) - would you have a link for that?

More to tech.

 

[Neilwood]

Speaking purely recreationally, if computer 1 with “A” algorithm gives 30 minutes BT and computer 2 with “B” algorithm gives 25 minutes, for 2 otherwise identical dives, How can computer 1 not be considered more conservative?

For a single dive within NDL, I would consider A to be more conservative.

Where it becomes interesting is second, third, fourth etc dives. How does the computer achieve its NDL limit for the second dive? If I dive at 59 minutes instead of over an hour, do I get penalised? If so, how much?

Given that virtually all of the bubble models (RGBM and VPM) are proprietary and don't give details of how/why "penalties" are imposed or the extents of them, my strong preference is for a Buhlman

 

[scrane]

Speaking purely recreationally, if computer 1 with “A” algorithm gives 30 minutes BT and computer 2 with “B” algorithm gives 25 minutes, for 2 otherwise identical dives, How can computer 1 not be considered more conservative?

I'm getting confused. I better head up.